var sliderbar = document.querySelector('.slider-bar');
var header = document.querySelector(".header");
var banner = document.querySelector(".banner");
document.addEventListener('scroll', function() {
    if (window.pageYOffset >= header.offsetHeight) {
        console.log('start');
        sliderbar.style.position = 'fixed';
    }
    if (window.pageYOffset <= header.offsetHeight) {
        console.log('over');
        sliderbar.style.position = 'absolute';
    }
})